Malecot's method of coancestry

Malecot's coancestry coefficient, ${\displaystyle f}$, refers to an indirect measure of genetic similarity of two individuals which was initially devised by the French mathematician Gustave Malécot.

${\displaystyle f}$ is defined as the probability that any two alleles, sampled at random (one from each individual), are identical copies of an ancestral allele. In species with well-known lineages (such as domesticated crops), ${\displaystyle f}$ can be calculated by examining detailed pedigree records. Modernly, ${\displaystyle f}$ can be estimated using genetic marker data.

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